The invention relates to a system for actuating at least one positioning flap on each wing of an aircraft, and to a method for monitoring the flap actuating system. The invention relates in particular to a high-lift system for actuating at least one high-lift flap on a wing of an aircraft, and to a method for monitoring the high-lift flap actuating system.
Document WO 2007/068413 describes a method and device for providing automatic load alleviation to a high lift surface system of an aircraft.
From the general state of the art it is known that the individual high-lift surfaces, also referred to as leading-edge slats, or trailing-edge flaps, are adjusted by means of a system comprising a central motor. In this arrangement the central motor drives a drive shaft that extends along the wing, which drive shaft transmits the driving torque to the individual flap actuators and to the leading-edge slats or to the trailing-edge flaps.
In this arrangement the high-lift system can be designed in such a manner that predetermined errors that occur in the system can be compensated for without this compromising the safety of the aircraft. To this effect, in particular, the installation of brakes and sensors for error detection, and/or secondary structural elements are provided in order to hold the high-lift surfaces in a defined position. If two actuators are coupled to an positioning flap, and if each actuator comprises an individual load path, then in order to compensate for any structural failure of one of the two actuators the respective other actuator can lock the high-lift surface in its position at that time. If several positioning flaps on the same wing are adjusted in each case with two actuators, each comprising an individual load path, a secondary flap connecting strut can be provided which couples the two high-lift flaps in such a manner that if an actuator of a positioning flap fails, the positioning flap is held by the respective other positioning flap, by way of this flap connecting strut, so that the load of the defective positioning flap is transferred to the adjacent positioning flap.
In this high-lift system the secondary flap connecting strut forms a second load path in case of failure of an actuator, i.e. in case the actuator is defective. In normal operation the system is kept in position in the central drive by means of brakes. If, for example, a transmission shaft suffers a fracture, the system is stopped by the wingtip brakes positioned on the outside of the right-hand wing and the left-hand wing.